An aerofoil shaped body is a three dimensional body having an aerofoil cross section (2-D), and is otherwise known as a 3-D aerofoil. Aerofoil bodies typically include a torsion box comprising upper and lower covers (or skins) on either side of a frame comprising spanwise spars and chordwise ribs. At least one spar is provided for each wing, although two or more is more common. In an aircraft wing, the torsion box is otherwise known as a wing box. The covers may also be reinforced with stringers, extending generally spanwise.
Traditionally extensive use has been made of lightweight metallic materials such as Aluminium in aircraft wing design. Mainly for ease of manufacture, the spars are conventionally substantially straight. In recent years there has been a move towards ever increasing use of composite materials, particularly fibre reinforced polymer matrix composites such as carbon fibre reinforced plastic (CFRP), in aircraft wings to replace more conventional metallic materials such as aluminium. Composite materials open up many manufacturing possibilities that have previously constrained traditional metallic aircraft design.
The leading and trailing edge regions of an aircraft wing are typically used to house a variety of aircraft systems and components, including leading and trailing edge high lift devices, wiring, etc. With straight spars, one or more highly space constrained pinch points may arise. On some aircraft wing designs a kink may be imposed on the spar to create to overcome a space constraint issue. Nevertheless a kinked spar still comprises two substantially straight portions either side of the kink. The joints between the straight spar sections typically necessitates joint plates which add weight, complexity and cost. This is true of current metallic and composite spar designs.
Current composite aircraft wing design comprises separate covers and spar manufacture which are then assembled together.
Reducing parts count and assembly time is of significant interest for high production rates.